Cathode ray tube deflection and high voltage apparatus



March 4, 1958 f Cl C, IDEN 2,825,850

Y GATHODE RAY TUBE DEFLECTION AND HIGH VOLTAGE APPARATUS Filed Maron 31,1955 2 sheets-sheet 1 /l l INVENTOYR.

March 4, 1958 C, C, IDEN 2,825,850

CATHODE RAY TUBE DEF'LECTION AND HIGH VQLTAGE APPARATUS Filed March 31,1955 I 2 Sheets-Sheet 2 Ide CA'H-E RAY TUBE DEFLEC'HN AND HES-ll VLTAGEAPP t f'i TUS Charles C. iden, Haddon Heights, N. J., assigner to odioCorporation of America, a corporation of Eclair The present inventionrelates to new and improved apparatus for furnishing both the highunidirectional potential for a cathode ray tube anode and theelectromagnetic energy for causing an electron beam within such tube toscan a predetermined pattern.

More particularly, this invention relates to an improvenient in thecombination high voltage and deflection output transformer such as isconventionally employed in conjunction with television receiverkinescopes.

Since electromagnetic deflection coils have a certain amount ofinductance, some stored energy is present in the coils the end of eachdeflection cycle. It is possible, through the use of a damping tube ordiode, to use a portion of such stored energy for producing a part ofthe voltage variations employed in deilecting the cathode ray beamduring the initial portion of the next succeeding scanning cycle.reaction scanning. The deflection coils also have certain inherentdistributed capacities which, together with their inductance, producetuned circuits having predetermined frequencies. During the go time,which is the time of the useful trace of the scanning beam, energy isstored in the magnetic field of the transformer and deflection coils.The energy contained in the coils is permitted to produce a half cycleof free oscillation during the ilyback time and, at the time of suchhalf cycle of oscillation, the damper diode is employed to control orabsorb the remaining energy, whereby to suppress substantiallycompletely the remaining cycles of oscillation. Since it is desirablethat the high voltage or accelerating potential required for operationof the kinescope also be derived in an efficient manner, it has becomecustomary to combine the functions of deilection and high voltagederivation in a single apparatus in which use is made of the inductivenature of the deflection circuits. That is to say, most present-daytelevision horizontal deflection circuits include means such as a poweramplifier tube for driving a sawtooth current wave form through atransformer which couples the sawtooth energy to the deflection coils.r.through the agency of a voltage step-up winding, the flyback pulsesproduced in the circuit inductances during the scanning retraceintervals are applied to a rectifier tube and filtered to afford ahigh-unidirectional potential for application to the nal anode of thekinescope. The present applicant has found that the high frequencyringing may be properly harnessed whereby to afford increased eiciencyin the dellection function of the apparatus while controlling its highvoltage-deriving function.

lt is a primary object of the present invention to provide noveldeflection land high voltage transformer rneans for use in highefficiency deflection and high voltage production.

By way of background, and as has been alluded to briefly above, it willbe understood that, in the case ol' the wellknown auto transformerarrangement, the damper tube conducts heavily at the end of retracetime, thereby approximating a short circuit across what may beconsidered as the secondary winding of the transformer, During the Suchaction is Well-known and is termed u Z,Z5,850 Patented Mar. 4, 1958latter portion of the scanning period, the horizontal output tubeconducts heavily, whereby to approximate a short circuit across what maybe considered the primary and secondary portions of the autotransformer. As will be appreciated by those skilled in the art, thereexists a leakage inductance between the high voltage step-up winding(tertiary winding) and the remaining portion of the transformer, whichlealae inductance is responsible, at least in part, for the ringing orhigh frequency oscillation mentioned supra.

The present invention has for another of its objects that of controllingthe frequency of the ringing which results from the leakage inductanceand its associated inherent capacities in such manner as to providecontrolled high voltage and optimum deflection efficiency.

In general, the present invention provides means for controlling thefrequency of the described ringing in such manner as to phase theringing wave form so that the ringing voltage combines with the flybacl:pulses to increase their ariplitude and, secondly, combines with thecurrent through the damper tube in a manner calculated to increase theamount of sav/tooth current which may be applied to the system by thepower tube, whereby to increase the eiciency of the deflection systemproportionately. ln accordance with the present invention, such controlof the ringing frequency is aorded by increasing the distributedcapacity-to-ground of the tertiary or stepup winding of the autotransformer. This increased capacity, when of the proper value, controlsthe frequency of the ringing to phase it correctly with respect to theilyback pulses and the deflection current.

As will be appreciated, the present invention requires only a simplechange in existing deflection and high voltage transformers in order tobring about the improved results set forth herein. Additional objectsand advantages of the present invention will become apparent to personsskilled in the art from a study of the following detailed description ofthe accompanying drawing, in which:

Figure l illustrates, by Way of block and schematic circuit diagram, atypical television receiver including a combination horizontaldeflection and high voltage transformer arrangement in which the presentinvention may he advantageously employed;

Figure 2 illustrates certain current waveforms to be described;

Figure 3 illustrates voltage waveforms useful in describing one aspectof the invention; and

Figures 4 and 5 are simplified views of a transformer constructed inaccordance with the invention.

Referring tothe drawing, and more particularly, to Figure 1 thereof,block lil represents that portion of a typical television receiver whichincludes a radio frequency amplifier, converter, intermediate-frequencyamplilier stages and the second detector. Details of these circuits arewell-known to those skilled in the art and need not be describedfurther. Examples of suitable circuits, however, may be found in anarticle entitled Television Receivers, by A. Wright in the March 1947issue of the RCA Review.

The input terminals of receiver lll are provided with compositetelevision signals which are intercepted by an antenna l2. These signalsare amplified by the receiver and demodulated in the usual manner sothat they appear at output terminal 14, which terminal is indicated forconnection to the beam intensity controlling electrode of the cathoderay image-reproducing device lo. The video signals demodulated withinthe receiver 10 are or may be suitably clipped to provide horizontal andvertical synchronizing pulses for application to the sync separatorcircuit IS via lead Ztl. The horizontal sync pulses then appearing atoutput terminal 22 of the sync separator are applied for synchronizationof the horizontal deflection is coupled to the control electrode 32 of ahorizontal deflection output discharge tube 34. Suitable biasingpotential for the discharge tube screen electrode 36 is conventionallysupplied from a source of positive potential indicated at terminal 3S as+B through a screen dropping resistor 40 which is, in turn, by-passed tothe cathode 42 via a capacitor 44. A self-biasing cathode resistor 46whose value is chosen in accordance with the desired operating bias foramplifier 34 is connected in the cathode circuit of the tube and isbypassed by capacitor 48.

The anode S0 of amplifier 34 is connected to a terminal 52 of anauto-transformer 54 which includes an auxiliary step-up winding 56connected to the anode 5S of a highvoltage rectifying diode 60. Thecathode lament 62 of the rectifier 6l), energized by a winding 63 on thetransformer 54, is connected to ground through a tilter capacitor 64, sothat high voltage for the final anode (not shown) of kinescope 16 may beapplied to the high-voltage terminal 68. The lower terminus 7i! of theauto-transformer 54 is connected through a TB-boost capacitor 72 and alinearity control inductance 74 to a source :of +B potential at terminal76.

Another capacitor, such as that indicated at 78, which aids in thelinearity control action of the inductance 74, is directly connectedfrom the auto-transformer terminal 70 to the +B terminal 76. Thehorizontal deflection winding 80 of the cathode ray deflection winding80 of the cathode ray deflection system is connected in shunt with thatportion of the auto-transformer between terminals 79 and 81. The dampingdevice which comprises, by way of illustration, the diode 82, isconnected in damping relation with the yoke Winding 80 through the B-boost capacitor 72 vand the linearity inductance 74 taken 1n combinationwith the capacitor 78. Accordingly, the anode 84 of damper diode 82 isconnected with the +B terminal 76 through the linearity inductance 74,while the diode cathode 88 is connected to a suitable point 90 on theauto-transformer.

As thus far described, the apparatus of the drawing is in accordancewith conventional practice. Since the operation of reaction-scanningapparatus is well known, it f need not be described in detail here. Afull analysis of such operation is given, for example, in an articleentitled Magnetic Deliection Circuits, RCA Review, September 1947, by O.H. Schade.

current will pass from the positive power supply terminal .1

76 through the inductance 74 and through the diode 82 to the transformer54. Such current ow induces some deliection voltage and current inthetransformer which causes a substantially linear rise in deiiectioncurrent through the yoke winding 80. At time t2, corresponding to thecommencement of the retrace interval Vof the deflection cycle, thedischarge tube 34 becomes non-conductive' and the magnetic eld in theauto-transformer and yoke then collapse, causing oscillation of theprimary resonant circuit (i. e. the yoke .and its distributed capaci-Briefly, however, it is to be noted that the bias on the horizontaloutput tube 34 is -lil tance) at its self-resonant frequency which isnormally at least four to live times that of the deflection frequency.

After one-half cycle of free oscillation, the voltage appearing acrossthe horizontal winding 80 is of such polarity as to cause the diode 82to conduct, thereby damping the energy magnetically stored in the yoke.The direction of the damping current through the diode S2, in accordancewith well-known reaction scanning principles, provides the rst portionof the sawtooth through the winding 30, which portion corresponds to theinterval between instants t3 and t4 of the sawtooth 24'. By the time t.,is reached, the horizontal discharge tube 34 will have been renderedconductive and this time, by reason of the bias across capacitors 72 and78, the diode 82 will not conduct as heavily, thereby causing most ofthe horizontal output tube anode current to liow through the autotransformer section between terminals 90 and 70.

Also during the retrace interval (i. e. between times t2 and t3) thecollapse of the magnetic eld in the autotransformer and yoke as abovedescribed results in the production of a high, unidirectional pulseacross the transformer tertiary winding 56. The amplitude of such pulseis proportional to the quantity where L is the inductance of the circuitand represents the rate of change of current therein. By virtue of thevoltage step-up action of the tertiary winding 56 of the transformer 54,the pulse is increased in amplitude to provide additional high voltagepotential, after rectification by the diode 60, for the kinescopeterminal 68. In addition to the desired voltage pulse produced by thetransformer during the retrace interval, there is additionally produceda ringing voltage train following the pulse and of a frequency which isdetermined by the usual formula m Zm/L-C' where L is the inductance ofthe circuit and C its capacity, including distributed capacity of thetransformer tertiary winding.

As pointed out in U. S. patent application Serial No. 439,956 tiledjointly by the .present applicant and P. M. Lufkin on June 29, 1954, theperiod of the ringing voltage train may be increased from its value T tothe longer value T by decreasing the ringing frequency and, specically,by increasing the leakage inductance between the tertiary winding 56 andthe primary winding of the transformer, which may be considered as thatbetween terminals 52 and 70.

The leakage inductance between two concentric windings of a transformeris proportional to the quantity where c is the length of a turn midwaybetween innermost and outermost layers, a is the distance between thetwo windings, conductor to conductor, d1 and d2 are the build-ups of thetwo windings (all of the forego ing dimensions being expressed ininches) and N is the number of turns of the winding to which the leakageinductance is referred. Since the build-up d1 of the primary winding ofthe transformer 54 in Figure l is normally fixed by such considerationsas the primary impedance direct current resistance, flux density in thecore and minimum primary to secondary leakage inductance, control of theleakage inductance of the tertiary Winding with respect to the rest ofthe winding may be had by changing the parameter a, namely, the distancemeasured radially between the windings. As may be determined from theforegoing expression for leakage inductance, the leakage inductance istherefore increased as a direct function of the spacing between thetertiary winding and the remainder of the transformer and, secondarily,by the increase in the mean winding diameter (referring to the parameterc). At the same time, as will be understood from the following formula,the distributed capacity of the tertiary winding is increased only bythe increase in the mean diameter of the tertiary winding:

Q'SCZZ Ulti-12 faracl Where c is the mean length of turn of the winding;l is the length of winding (i. e. wire traverse); d is the distancebetween layers (all in inches); T is the number of layers of wire in thewinding; and lc is the average dielectric constant of the insulationmaterial.

An important advantage afforded by the increased leakage inductanceresulting from spacing the tertiary winding from the primary-secondarywinding and the resultant ringing re-phasing is that of increasing theeiiiciency of the deflection circuit. This action is accomplished byvirtue of the fact that the spacing between the tertiary and primarywindings of the transformer also changes the phase of the leakageinductance ringing voltage which is coupled into the damper tubecircuit. Speciiically, the amount of horizontal driving voltage whichmay be impressed upon the deflection transformer 5d by the horizontal.output tube 34 is limited by the damper tube current. That is to say,maximum permissible drive is normally attained when the damper tubecurrent is reduced to zero in the vicinity of the middle of the scanningline, such cessation of damper tube conduction being manifested by abright vertical line in the center of the kinescope raster. As statedabout in connection with the general description of the deflectioncircuit operation, it is the damper tube current (between times t3 andt4) which furnishes approximately half of the deiiection energy in eachhorizontal line scan. lt has been found that, for optimum performance ofsuch a reaction scanning arrangement to be realized, it is necessary forthe driver tube 3d to furnish an excess of current to the deectioncircuits, so that the damper tube may conduct continuously during the gotime.

A typical Icurrent wave form through a damper tube such as the tube S2in Figure l is illustrated by wave form (a) of Figure 2, in which the gotime or scanning period is designated as '1`s. By virtue of theconnection of the damper diode as shown, current therethrough is in thenegative direction as is necessitated by the requirement that the dampercurrent deilect the electron beam within the kinescope to the oppositeside of its central position from that direction in which-the drivertube current deects it. The dotted line portion 98 of the damper cur- C'(distributed):

rent waveform (a) of Figure 2 represents the current for ,t

a given amount of drive from the horizontal output tube 34. As theamount of drive is increased, the current through the damper tube alsoincreases as indicated by the solid line portion 114 of the waveform.The rippled portions of the waveform are the result of the ringingenergy from the leakage inductance of the transformer which is coupledinto the damper tube circuit. The minima or peaks ltltl of the dampertube current waveform are at the zero reference line and indicate dampertube cutoff, which constitutes the limiting condition for the amount ofdrive which may be furnished by the tube 34. Since the eticiency of thecircuit is generally proportional to the amount of drive which may besuccessfully applied to the circuit, it is desirable to increase thecurrent through the damper tube (i. e. in the negative direction) sothat the peaks lidi) do not reach zero or, stated otherwise, so that thedamper tube is not cut ot during the middle of the scanning line. Thedamper tube current during the middle portion of the scanning line maybe increased by so phasing the ringing voltage train of the leakageinductance that it adds to the damper tube current in such manner as toincrease that current (in its negative direction) by adding a negativehalf cycle of the ringing energy to the damper tube current during thecentral part of the scanning line interval, thereby preventing thedamper tube current from being cut oit. The rephasing of the ringingvoltage required for increasing the eiciency of deection has been foundto be as illustrated in waveform (b) of Figure 2. This is to say, thespacing of the tertiary winding 56 from the primary winding of thetransformer 54 which increases the leakage inductance therebetweenwhereby to increase the period `of the ringing voltage train provides anegative half cycle of ringing voltage near the peaks of the dampercurrent wave form so that the resultant damper current is changed tothat shown by waveform (b) of Figure 2 wherein the peak 106 is morenegative than the zero reference. Thus the amount of drive which may befurnished by the horizontal output tube 34 is increased so that greaterdeflection eciency is possible.

it has also been found, as pointed out in the abovecited patentapplication, that the phasing of the ringing voltage as accomplished inthe interest or increasing the amplitude of deflection or detlectioneiiiciency is substantiaiiy the proper phase for increasing theampiitude or the high voltage pulses which are rectitied to provide ahigh unidirectional potential for application to the kinescope anode.The high voltage pulse and its associated ringing voltage is illustratedby the waveforms (a) and (b) of Figure 3, wherein, as may be seen, thehigh voltage pulse M2 is foliowed by a ringing voltage litfi having aperiod equal to it may be seen from wavetorm (a) of Figure 3 that thenal half-cycle of the ringing waveform titte (i. e. that immediatelypreceding the second ilyback high voltage pulse T Z') is at or near itsminimum value. Experimentation has shown that such phasing of theringing waveform effectively decreases the amplitude of the pulse 102 asthrough a pro-cess in the nature of algebraic subtraction of thevoltages. it is, however, possible to increase the amplitude of theensuing high voltage pulse by properly phasing the ringing waveform 164with respect to the commencement of the retrace time. Thus, when thetuning of the transformer is adjusted as by providing a spacer betweenthe primarysecondary winding of the transformer and the tertiary windingto increase the leakage inductance of the transformer so that the periodof the ringing waveform is changed from the period T of waveform (a) ofFigure 3 to the longer period T of waveform (b) of Figure 3, the iinalportion of the ringing voltage train 164 will be at or near its maximumvalue immediately preceding the commencement or the retrace period Tr.Thus the ringing voltage, phased as in waveform of Figure 3, effectivelyadds to the high voltage pulse to increase its amplitude.

The present invention provides novel means affording additional controlover the tuning orF a transformer of the type in question for increasingits eiiiciency. Where, for example, the operational requirements of sucha transformer are such that the frequency of the ringing voltage cannotbe .completely controlled by the spacing of the tertiary winding thereoffrom its primary-secondary winding or where the value of the highvoltage iiyback pulses to be produced necessitates the use of a smallernumber of turns for the tertiary winding than that which aords thenecessary amount of distributed capacity and leakage inductance, asexplained, the requisite tuning of the transformer may be accomplishedthrough the agency of the present invention which, in a simple andinexpensive manner, increases the distributed-capacity-to-ground of thetertiary winding. Since the frequency of the ringing is, as has beenexplained, inversely proportional to the square root of the product ofthe leakage inductance and the distributed capacity, such increaseddistributed ca- 7 pacityof the tertiaryv winding can beadvantageously-eniployed in maintaining the LC product constant.

That is tosay, and assuming by way of example that the spacing betweenthe primary-secondary winding and the tertiary winding of a transformerhas been adjusted to provide a leakage inductance of the proper valuewhich, when tuned with the capacities of the transformer, affords aringing voltage of the proper phase as illustrated by the waveforms ofFigure 2 but that the high voltage pulses are greater than required fora given transformer design, reduction of the number of turns of thetertiary winding, While effective to reduce the amplitude of the highvoltage pulses, has been found to de-tune the transformer in anundesirable manner so that it no longer affords the optimum efficiencyfor deflection. The reason for such cle-tuning will be understood asstemming from two facts. First of all, the reduction in number of turnsof the tertiary winding necessarily kdecreases the distributed capacityof the tertiary winding to ground. Secondly, since the leakageinductance is generally proportional to the square of the number ofturns of the winding, that parameter is also decreased. The decrease ofboth distributed capacity andthe leakage inductance thus brings about achange in the frequency of ringing. If such a frequency change is sogreat as to render its correction by additional spacing between thewindings impracticable for some reason, the correction thereof may bemade in accordance with the present invention as now will be explained.

Figure 4 illustrates by way of a simplified, vertical sectional view, acombination deflection and high voltage transformer such as thatillustrated schematically in the circuit diagram of Figure 1, and, inthe interest of clarity, reference numerals identical to those used inFigure Il designate corresponding portions of the structure of Figure 4.The transformer 54 includes a lirst winding from terminal 52 to terminal70 which comprises the primarysecondary winding of the transformer. Thiswinding is cylindrically arranged about a cylinder 101 formed of asuitable insulating material. An iron vcore in the form of two C-shapedmembers 106 and 108 is provided in a conventional manner. The ends ofthe C-shaped members 106 and 108 within the insulating cylinder or coilform 101 may be spaced apart several mils, as shown, for the purpose ofeliminating saturation due to plate current (D.-C.) flowing fromterminal 90 to terminal 52. The tertiary winding 56 starts at the point52 and ends at the finish lead 106 which is adapted for connectiorL tothe anode 5S of the high voltage rectifier diode. The tertiary winding56 is wound concentrically with respect to the primary winding and isspaced therefrom a predetermined distance a by means of an insulatingspacer 110 of the proper thickness, which spacer may, for example, bemade of such material as a phenol formaldehyde resin. Electricallyconnected to the finish lead of the tertiary winding 56 is a copperstrap 116. The copper strap 116 is of such length as to surround asubstantial portion of the periphery of the tertiary winding 56, asshown in the view of Figure 5. A strip 118 of iusulating material (e. g.0.003-inch kraft paper) serves to insulate the copper strap 116 from thetertiary winding 56. As may also be seen from the showing of Figure 4,the copper strap is of greater width than the width of the winding 56,for purposes which will become more apparent hereinafter.

rlhe following specifications afford a specific example of a transformerconstructed in accordance with the present invention for providing 90deiiection and 15 kilovolts of high voltage in an arrangement employinga horizontal output tube of the 6BQ6 type and a rectifier of thedesignation lXZB: the primary-secondary winding comprises 910 turns(plus or minus 1%) of 0.007 heavy formex wire, layer-wound, with onethickness of 0.005-inchkraft paper between layers. The winding, having85 turns per layer with a traverse of`0.875inch,

8 is vtappedI at points corresponding to the terminals 73,' 81, 90 and52 (Figure 1) at 100 turns, 570 turns, 620 turns and its terminus.

rfhe tertiary winding comprises 1100 turns (plus 4or minus 1%) of 0.0045heavy formex wire, layer-wound, 24 turns per layer, with a traverse of0.250-inch, one thickness of 0.003 kraft paper being inserted betweenthe layers for insulation.

The insulatingrspacer 108 between the primary-secondary winding and thetertiary winding for the described transformer has a wall thickness of0.220-inch. The copper strap employed has dimensions of 1/2-inch by 7%-inches and is of 0.003-inch in thickness and is electrically connectedto the finish lead 106 of the tertiary winding and to the lead 120 whichis connected to the anode of the lXZB rectiier tube, the strap beingwrapped around the tertiary winding in the direction of the winding.

In order to provide a quantitative understanding of the action of thecopper strap in tuning the transformer as explained above, the followingillustrative data are presented regarding a test transformer: With atertiary winding of 1200 turns, the leakage inductance of thetransformer was found by measurement to be approximately equal to 97.7millihenries (i. e. from the high voltage winding to the damper tube).With 50 turns of the tertiary winding removed, the measured leakageinductance was 91.3 millihenries (a difference of approximately 6.4millihenries). Under the first conditions, the frequency of ringing wasfound to be 138 kilocycles per second, while the frequency of ringingunder the second described conditions was 142.5 kilocycles per second.By substituting the measured values of leakage inductance and frequencyin the formula F=1/z1r\/LC, the distributed capacities for the two caseswere found to be only slightly different. Specifically, the distributedcapacity for the first case (with 1200 turns) was calculated to beapproximately 13.6 turf. The second case (1150 turns) the distributedcapacity was calculated to be approximately 13.5 turf., so that the lossof distributed capacity is measured in fractions of a microfarad. Thefunction of the copper strap surrounding the tertiary winding of thetransformer is, as has been stated, that of making up the deficiency ofthe lost distributed capacity and leakage inductance, so that thecapacity added by the strap may be calculated as being approximately 1auf. This additional capacity thus returns the frequency of ringing toits proper value (i. e. 138 kilocycles per second, as indicated above)and in a simple, inexpensive manner.

It has also been found, in general, that the capacity added to thetransformer by the copper strap around the tertiary winding variesgenerally in proportion to the length of the copper strap and to itswidth. As a practical matter, experimentation has shown that thecapacity added by the strap is most noticeable when the strap is nearthe essentially grounded portion of the ferrite core (the lower portionin Figs. 4 and 5).

Measurements have also shown that the use of the copper strap for tuningthe transformer for optimum ringing increases the retrace time by amatter of only a tenth of a microsecond, which increase in time is soslight as to be readily remedied, if desired, by making a slightadjustment in the capacitive loading of the yoke itself. That is to say,the loading effect of the capacitor shown in Figure 1 as connectedbetween terminal 81 on the transformer and ground may be decreasedslightly by connecting the ungrounded plate of the capacitor to a lowerimpedance point on the transformer which has the effect of shorteningthe retrace time.

From the foregoing, it will be recognized thatv the present inventionprovides novel but effective means for tuning a transformer of the typein question for optimum deilection deciency and in a manner which issubstantiallyindependent of the number of turns ofthe winding thereof.rlhe tuning may, therefore, be madefinaccordance with the presentinvention'independently of the required amplitudeof the steppedeup yback:pulse twhich is applied tothe .high .voltage :rectifier vHavingthusdescribedmy invention, what I claim as new and desire to secure byLetters Patent is:

1. A deflection and high voltage transformer comprising iirst and secondserially connected inductive windings concentrically disposed withrespect to each other; an insulating spacer member between said firstand second windings for spacing one of said windings radially from theother in such amount as to provide aV predetermined leakage inductancebetween said first and second windings; and capacitive means connectedto the outer one of said concentrically disposed windings, said windingshaving distributed capacity which forms a ringing circuit with suchleakage inductance having a certain resonant frequency, said capacitivemeans being of such value as to tune said inductance and distributedcapacity to a frequency lower than said certain frequency.

2. A cathode ray tube detiection and high voltage transformer comprisinga rst cylindrical, inductive winding adapted to be connected at one endto a deiiection output amplifier and at its other end to a source ofoperating potential; a second cylindrical winding around said firstwinding and concentric therewith; a connection between one end of saidsecond winding and said end of said rst winding and such amplier, saidwindings having distributed capacity in circuit therewith forming aringing circuit having a resonant frequency determined by such capacityand the inductance of said windings including leakage inductancetherebetween; and capacitive means connected electrically to the end ofsaid second winding remote from the end connected to said first windingfor increasing the capacity of such ringing circuit in such manner as toalter the frequency of such ringing.

3. A deflection and high voltage transformer for use in conjunction witha cathode ray tube and adapted to couple energy from a deectionamplifier to an electromagnetic deflection winding and to a rectifyingcircuit for producing a high unidirectional potential for application toan electrode of such tube, said transformer comprising: a primarywinding adapted for connection to both such amplifier and to suchdeflection winding; a second winding serially connected to said primarywinding for coupling energy to such rectifying circuit, said secondwinding being concentric with and around said primary winding, saidtransformer having inherent capacity forming a part of a resonantcircuit of such character as to produce ringing of a certain frequency;and a strap of conductive material electrically connected to the end ofsaid second winding remote from its connection to said rst winding, saidstrap surrounding a selected portion of said second winding.

4. A combined deflection and high voltage transformer for use inconjunction with a cathode ray tube, said transformer comprising: afirst transformer winding having an input terminal adapted forconnection to a source of deection energy and a pair of output terminalsfor connection to an electromagnetic deection winding; a secondtransformer winding electrically connected serially with and physicallyconcentric with respect to said iirst winding in such manner as to be inenergy transfer relationship therewith, said second winding having anoutput terminal for connection to a rectifying circuit of the typeadapted to rectify recurrent yback voltage impulses produced in saidtransformer whereby to produce a high, unidirectional potential forapplication to such cathode ray tube; means for spacing said secondWinding radially outwardly from said iirst winding a distance suicientto produce a leakage inductance between said rst and second windingsgreater than that available in the absence of said spacing means, saidwindings having distributed capacitance forming a ringing circuit withsuch leakage inductance having a certain frequency; and means forming acapacitive path from said output terminal of said 10 second :windingrto.afpoint of -xed potential fiorentina ksuch .ringing lcircuit to afrequencyl lower than -said Y, certain frequency.

5. A combined deflection and high voltage transformer for use inconjunction with a cathode ray tube, said transformer comprising: afirst transformer winding having an input terminal adapted forconnection to a source of deflection energy and a pair of outputterminals for connection to an electromagnetic deflection winding; aSecond transformer Winding electrically connected seriallylwith andphysically concentric with respect to said first winding in such manneras to be in energy transfer relationship therewith, said second windinghaving an output terminal for connection to a rectifying circuit of thetype adapted to rectify recurrent flyback voltage impulses produced insaid transformer whereby to produce a high, unidirectional potential forapplication to such cathode ray tube, said transformer having inherentcapacity whereby to forni a resonant circuit of such character as toproduce ringing of a certain frequency; and capacitive means connectedto said output terminal of said second winding for increasing thecapacity of said transformer in such manner as to change the period ofsuch ringing.

6. A combined deflection and high voltage transformer for use inconjunction with a cathode ray tube, said transformer comprising: afirst transformer winding having an input terminal adapted forconnection to a source of deection energy and a pair of output terminalsfor connection to an electromagnetic deflection winding; a secondtransformer winding electrically connected serially with and physicallyconcentric with respect to said first winding in such manner as to be inenergy transfer relationship therewith, said second winding having anoutput terminal for connection to a rectifying circuit of the typeadapted to rectify recurrent flyback voltage impulses produced in saidtransformer whereby to produce a high, unidirectional potential forapplication to such cathode ray tube, said second winding havinginherent capacity; leakage inductance between said second winding andsaid first winding of a certain value forming a resonant circuit withsaid capacity whereby ringing is produced at a given frequencydetermined by the values of said leakage inductance and said inherentcapacity; means for Spacing said second Winding radially from said rstwinding by a predetermined` distance such that said leakage inductanceis increased in an amount sufficient to decrease said given ringingfrequency to a lower frequency; and means comprising a conductive memberconnected electrically to said output terminal of said second Windingfor increasing the capacity across said second winding in such manner asto decrease said frequency of ringing below said lower frequency.

7. A combined deflection and high voltage transformer for use inconjunction with a cathode ray tube, said transformer comprising: afirst transformer winding having an input terminal adapted forconnection to a source of deflection energy and a pair of outputterminals for connection to an electromagnetic deflection winding; asecond transformer winding of cylindrical form electrically connectedserially with and physically concentric with respect to said firstWinding in such manner as to be in energy transfer relationshiptherewith, said second Winding having an output terminal for connectionto a rectifying circuit of the type adapted to rectify recurrent iiybackvoltage impulses produced in said transformer whereby to produce a high,unidirectional potential for application to such cathode ray tube, saidsecond winding having inherent j capacity; leakage inductance betweensaid second winding "El 12 yback impulses; and a strap of conductivematerial con- 2,513,160 Friend June 27, 1950 nected electrically at oneend to said output terminal of 2,620,457 Crooker Dec. 2, 1952 saidsecond Winding and disposed in conformity with the 2,678,413 Adler etal. May 11, 1954 periphery of said second Winding for decreasing thefrequency of such ringing. 5

References Cited in the file of this patent UNITED STATES PATENTS2,320,537 Santos June 1, 1943 lo

